Pivot-pin for teeth.



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TH MORRIS I ERS C0 PHOTO ITN VIASNINGTON D C V PATENT Patented July 7,leo.

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EGBERT A. CLARK, oEwAsHINGToN, DISTRICT CE COLUMBIA.

.PIVOT-PIN FOR TEETH.

1 SPECIFICATION forming part of Letters Patent No. 732,922, dated July7, 190e.-

f Application filed May 9, 190s. seal No. 156.335. (No man.)

To @ZZ whom t may concern;

Be it known that LEGBERT A; CLARK, a sub` ject ofthe King of -England,residing at Washington, in the District of` Columbia, have inventedcertain new and useful Improvements in Pivot-Pins for Teeth; and I dohereby de- Clare thefollowing'to be a full, clear, and eX- actdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to new and useful improvements in pivot-pinsforteeth; and the object of the invention is tor produce ,a fastenin gdevice for holdin g the root to the Crown of a tooth comprising a pinwllich shall be so constructed 'as to conform as nearly as possible tothe anatomical lines of the canal of a single-rooted tooth, while theportion of the pin at the point of union between the root and Crown hasits greatest dimension to withstand the excessive strain which comesupon it at the base of the crown.

The invention consists, further, in the provision of a pivot-pin thebase or crown-engaging end of which is rectangular-shaped `with a shankportion having its opposite broad faces at substantially right angles tothe length of the head and longitudinally grooved, whereby the broadestportion of the Ahead of a pin when fastened within the retherooti-canalhaving its widest portion con# forming to the broadestportion of the root, while the depressions formed longitudinally `dividethe pin into two portions of unequal dimensions, adapting the pin to beslitted longitudinally to form double points to enter the two canals ofa first bicuspid-root- Another feature of my invention comprises apivot-pin having a base or crown-engagin g portion which has itsgreatest dimension in a plane at right angles to the widest'portion .of`the, pin which engages the rootcanal,

whereby a greaterthickness of crown of a tooth intervenes between theend of the pin and the bite of the tooth than is the case with pins andcrowns which are comlnonly employed. A

My invention is illustrated in the accompanying drawings, in which-Figure l is a side elevation of a pin made in accordance with myinvention. Fig. 2 is a cross-sectional View takenx on line 2 2 of Fig.l. Fig. 3 is a crossfsectional view taken on line 3 3 of Fig. l. Fig. 4is a view in elevation of the pin looking at the latter at right anglesto the showing in Fig. l. Fig. 5 is a longitudinal sectional viewthrough a root and crown held together by my improved pivot-pin. Fig. 6'is a cross-sectional view on line 6 G of Fig. 5. Fig. 7 is across-sectional view on line 7 7 of Fig. 5, and Fig. 8 is aCross-sectional view on line 8 8 of Fig. 5. Fig. 9 is a longitudinalsectional view througha tooth and crown taken on line 9 9 of Fig. 5.

Fig. l0 is an enlarged detailed view of a crown of a tooth, showing thepin-receiving recess or cavity in dotted lines. Fig. 1l is a rear Viewof the crown. Fig. 12 is a longi tudinal sectional view through the rootof a bicuspid, having the crown held together by my pivot-pin, thelatter being shown as ap` plied to the two prongs of the root; and Fig.13 is a view showing my pivot-pin with the two points formed to enter adouble canalcavity of a root.

Reference now being had to the details o f the drawings by letter, Adesignates a pin, which may be made of any suitable metal found to bebest adapted for the purpose and is of substantially wedge shape, whiletwo of its faces have formed therein marked longi tudinal depressions D(shown clearly inthe drawings) and dividing the shank into two sectionsB and C of unequal dimensions, said depressions terminating at `the apexof the pin ill a notch E, in which the blade of a knife may be insertedwhen it is desired to separate the points for the reception of aninstrument to cut through the narrow wall intermediate the depressedportions when adapting the pin to enter a branching canal-cavity, asdisclosed in Fig. l2 of the drawings. Said pin is adapted ICO to conformas nearly as possible to the outline of the wall of the canal in a rootin order to prevent the cutting away of the wall of the root. At alocation adjacent to the entrance to the canal of the root the pin issubstantially square in cross-section, while the portion of the pinintermediate the inner ends of the depressions and the apex of the pinis divided by the depressions into two unequal portions, as disclosed bythe cross-sectional views in the drawings. In other words, saidlongitudinal depressions I) are formed at one side of the longitudinalcenter of the pin for the purpose of producing, when the points areseparated, two projections of unequal size to conform to canal-cavitiesof different sizes which are naturally formed in the roots. The portionof the pin which projects beyond the root has its greatest dimensions ina plane at right angles to the width of the pin inserted in the root,this detail being one of the essential features of the presentinvention, and the differences in the greatest dimensions of the pin'being clearly shown in sectional views 6 to 8, inclusive. The object offorming the head of the pin wid er in a plane at right angles to thewidest portion of the pin in the root is to bring the. head of the pinas far away as possible from the bite of the tooth without sacrificingthe strength of the pin, this being permissible by reason of the crownof the tooth being wider in a line parallel to the widest portion of thehead of the pin. After the root is ready for the reception of the pin afilling of cement F is inserted in the canal of the root F, and afterthe crown G, which has a recess G/ therein conforming to the generaloutline of the head of the pin, is inserted over the latter cement isinserted between the grooves H in the head of the pin andthe surroundingwall nl of the recess in the crown and the parts securely held together.

In Fig. l2 of the drawings I have shown the application of my pivot-pinto the roots of a bicuspid tooth in which the pin is slittedlongitudinally to enter the branching canal-cati ties.

In adjusting my pin it will be observed that the general outlines of thecanal-cavity are undisturbed, while the pin-is so constructed that thedepressed portion of the longitudinal center of the pin, in order toconform to the angled outlines of the canal-cavity and the crown, isprovided with a recess which has its greatest width in line with thewidest portion of the tooth to receive the head of the pin, which issubstantially of the same shape, and when it is desired to aline theteeth this may be easily done by changing the position of the crown inone direction or the other and at the same time insuring the crown andpivot from turning independent of each other and of the root. A

I am aware that it is common in the art to construct pivot-pins whichare iiat and tapering and which have longitudinal recesses which arecommonly baked with the formation of the crown of a tooth, and hence Ido not make claim for a pin of this character, but rather for a pinwhich is adapted, by its peculiar construction, to conform to thecanalcavities of the root and which is n'ot designed to be baked withthe pin, hence may be made of various metals, and one which will allowof the alining of the crown and which will throw the edge of the headaway from the bite of the tooth as far as possible and at the same timethrow the strength of the pivot at the point of union between the crownand tooth, where the greatest strain occurs.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is-

l. A pivot-pin forteeth, having a root-engaging portion withlongitudinal depressions in two of its opposite faces, and a head whichis broadest in a plane at right angles to said Agrooved faces, as setforth.

2. A pivot-pin for teeth, having a rootengaging portion, the broadtapering faces of which are longitudinally grooved, 4dividing the shankportion of the piny into ribbed sections of unequal dimensions, andprovided with a head having its widest dimension in a plane at rightangles to the grooved faces of 'the pin, as set' forth.

3. A pivot-pin for teeth, having a root-engaging portion, the broadtapering faces of which are longitudinally grooved a portion of theirlength, dividing the shank portion of the pin into two tapering ribbedsections which terminate in separate points, the broadest part of thehead of the pin being in a plane vsubstantially at right angles to theplane of IOS

